It has a land area of 719.34 km2, making it the smallest regency in East Java,[2] although it contains many of the southern suburbs of Surabaya and has a high population density.

Notes: (a) comprising 6 kelurahan (Gedang, Jatirejo, Juwetkenongo, Mindi, Porong and Siring) and 13 desa.

(b) comprising 14 kelurahan (Bulusidokare, Celep, Cemengkalang, Gebang, Lemahputro, Magersari, Pekauman, Pucang, Pucanganom, Sekardangan, Sidokare, Sidoklumpuk, Sidokumpul and Urangagung) and 8 desa.

(c) comprising 8 kelurahan (Bebekan, Geluran, Kalijaten, Ketegan, Ngelom, Sepanjang, Taman and Wonocolo) and 16 desa.

Today, crops that still produced in Sidoarjo are Rice, Banana, Papaya, Cassava, and several lowland vegetables.

Among this are : Jatim Taman Steel (Steel Manufacturer), Avian (Paints and building material), Tunggal Djaja (Paints Production), Maspion (Household durable goods), Japfa Comfeed (Feedmills and poultry), Interbat (Pharmaceuticals), Integra (Furniture), Tjiwi Kimia (Paper), Kimberly-Clark's Softex (Non-durable consumer goods), Unicharm (Non-durable consumer goods), Polygon Bikes (Bikes), Alumindo (Aluminium products), Sekar Group (Food processing), Hisamitsu (Pharmaceutical), Lighting Solutions (Lamp), ECCO (Footwear), Samator (Industrial gas and chemicals), Bernofarm (Pharmaceutical), Muntjul Diamond (Vehicle body), Charoen Pokphand (Agribusiness) and many more.

Garments, Food Processing, Footwear, Apparel, and Furniture are products that usually produced by small and medium manufacturers in Sidoarjo.

Many small and medium manufacturers produces Traditional Herbs, Machinery, Packaging, and Metal products.

While some scientists have speculated that the earthquake that struck Yogyakarta on May 27, the day before the well erupted, may have cracked the ground, creating potential pathways for the mud to reach the surface, others have suggested that the drilling procedure was faulty by not using a casing.

Gus Maksum, one of the thousands of Sidoarjo villagers displaced by the mud flow gives a detailed first-hand account of the first year of the disaster in his memoir Titanic Made By Lapindo.